The present invention relates to a straw tube for sucking a drink in a drinking container. More specifically, the present invention relates to a straw tube capable of preventing the pressure inside the drinking container from decreasing while sucking.
Beverage products enabling drinking of a drink in a drinking container by inserting a straw tube into a closed drinking container having a hollow part in the inside thereof are available on the market.
FIG. 12 is a view showing one example of a beverage product. This beverage product 40 is constructed by a rectangular parallele-piped container body 42 having formed on the upper surface thereof a sucking hole 41 sealed with a plastic film or the like and a two-stage straw tube 44 housed in a bag 43 and fixed to the lateral side of the container body 42. The xe2x80x9ctwo-stage straw tubexe2x80x9d as used herein means a straw tube where an inner tube and an outer tube different in the diameter are combined to allow free sliding for extension or retraction.
When drinking a drink in the container body 42, the two-stage straw tube 44 is extended by sliding the inner tube 45 and the outer tube 46, the plastic film sealing the sucking hole 41 is broken through by the distal end of the two-stage straw tube 44, the two-stage straw tube 44 is inserted into the container body 42. Then, the drink in the container body 42 is sucked through the basal end of the two-stage straw tube 44.
However, when the two-stage straw tube 44 is inserted into the container body 42 and the drink in the container body 42 is sucked, the pressure inside the container body 42 is reduced. As a result, the container body 42 is deformed, making the drinking inconvenient or when the sucking is interrupted or finished, air abruptly enters into the container body 42 through the two-stage straw tube 44 to generate uncomfortable noises.
To overcome these problems, a straw tube having a groove formed on the outer circumferential wall of the outer tube and extending in the longitudinal direction has been proposed, for example, in JP-U-A-59-70574 (the term xe2x80x9cJP-U-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese utility model applicationxe2x80x9d), JP-U-B-3-49570 (the term xe2x80x9cJP-U-Bxe2x80x9d as used herein means an xe2x80x9cexamined Japanese utility model publicationxe2x80x9d), Japanese Patent No. 2582005, JP-A-7-163450 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d), Registered Design No. 957695, JP-A-7-222664, JP-A-7-222665 and JP-A-7-322948.
As shown in FIG. 13, the straw tube having forming thereon such a groove can form a void 48 between the peripheral edge 47 of the sucking hole 41 on the container body 42 and the groove 51 on the straw tube 50, so that an air can be introduced even at the time of sucking. As a result, the pressure inside the container body 42 can be prevented from decreasing and the deformation of the container body 42 or the generation of uncomfortable noises can be inhibited.
However, the groove 51 on the straw tube 50 is shallow and therefore, the void 48 formed between the peripheral edge 47 of the sucking hole 41 and the groove 51 on the straw tube 50 is small. Depending on the case, the peripheral edge 47 of the sucking hole 41 is accustomed to the groove 51 on the straw tube 50 and the peripheral edge 47 of the sucking hole 41 clogs the void 48 during sucking. As a result, the pressure inside the container body 42 is often reduced.
Accordingly, an object of the present invention is to provide a straw tube for a drinking container of a type such that a straw tube is inserted into a hole provided on a drinking container and the drink is sucked through the straw tube, which can prevent the pressure inside the drinking from decreasing while sucking to ensure convenient drinking and no generation of uncomfortable noises. Another object of the present invention includes providing an apparatus and a method for producing the straw tube.
More specifically, the straw tube of the present invention comprises a tube having formed on the outer circumferential wall thereof a groove extending in the longitudinal direction and a convex streak adjacent to the groove and projecting outward from the datum level of the outer circumferential wall.
Also, the straw tube of the present invention comprises a tube having formed on the outer circumferential wall thereof a plurality of grooves extending in the longitudinal direction and a convex streak sandwiched by these grooves and projecting outward from the datum level of the outer circumferential wall.
The straw tube of the present invention may be a multistage straw tube comprising two or more tubes different in the diameter and combined to allow free sliding for extension or retraction.
The straw tube of the present invention may be a straw tube wherein a groove and a convex streak are formed on the outer circumferential wall of at least one tube of the two or more tubes.
The straw tube of the present invention may be a straw tube wherein a groove and a convex streak are formed on the outer circumferential wall of the outermost tube located in the outermost side of the two or more tubes.
Preferably, the number of the grooves is two and one convex streak is formed therebetween to come adjacent to these grooves.
The groove and the convex streak each preferably has a length of ⅓ to xc2xe the length of the tube on which the groove and the convex streak are formed.
The convex streak preferably has a height of 0.05 to 1.0 mm from the datum level of the outer circumferential wall of the tube on which the convex streak is formed.
The groove preferably has a depth of 0.1 to 0.8 mm from the datum level of the outer circumferential wall of the tube on which the groove is formed.
The straw tube of the present invention preferably comprises a propylene-xcex1-olefin random copolymer having a melt flow index of 3 to 16 g/10 min.
The propylene-xcex1-olefin random copolymer is preferably a propylene-ethylene random copolymer.
The ethylene content of the propylene-ethylene random copolymer is preferably from 2 to 20% by mass.
Furthermore, the straw tube of the present invention preferably comprises a propylene-xcex1-olefin block copolymer having a melt flow index of 3 to 16 g/10 min.
The propylene-xcex1-olefin block copolymer is preferably a propylene-ethylene block copolymer.
The ethylene content of the propylene-ethylene block copolymer is preferably from 2 to 20% by mass.
Still further, the straw tube of the present invention preferably comprises a homopolypropylene having a melt flow index of 3 to 16 g/10 min.
The apparatus for producing a straw tube of the present invention is an apparatus used for producing a straw tube comprising a tube having formed on the outer circumferential wall thereof a plurality of grooves extending in the longitudinal direction and a convex streak sandwiched by these grooves and projecting outward from the datum level of the outer circumferential wall. The apparatus comprises a rotating drum having formed on the outer circumferential wall thereof a plurality of tube loading grooves into which tubes are loaded and which extend in the axial direction, a female rod capable of being inserted into or drawn out from a tube within the tube loading groove by the reciprocation of a cam mechanism and having a plurality of grooves formed at the position corresponding to the surface of a tube exposed from the tube loading groove, and a male roller having a male mold which has convex streaks corresponding to the grooves of said female rod and is provided at a plurality of portions on the circumferential wall. The male roller is disposed such that the grooves of the female rod and the convex streaks of the male roller engage through a tube and wherein the female rod and the male roller are synchronized.
In the apparatus for producing a straw tube of the present invention, the female rod preferably has two grooves and the male mold provided on the male roller preferably has two convex streaks.
The method for producing a straw tube is a method for producing a straw tube comprising a tube having on the outer circumferential wall thereof a plurality of grooves extending in the longitudinal direction and a convex streak sandwiched by these grooves and projecting outward from the datum level of the outer circumferential wall. The method comprises a step of loading a tube into a tube loading groove formed on the outer circumferential wall of a rotating drum and extending in the axial direction thereof, a step of inserting into the tube a female rod having a plurality of grooves formed at the position corresponding to the surface of the tube exposed from the tube loading grooves, and a step of engaging the grooves of the female rod within the tube and the convex streaks of a male mold provided on a male roller, through the tube.
In the method for producing a straw tube of the present invention, the female rod preferably has two grooves and the male mold provided on the male roller preferably has two convex streaks.